﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace HHMES.Common
{
        /// <summary>
        /// 校验值计算
        /// 支持按位异或校验（XOR)
        /// 支持CRC16查表法校验
        /// 支持CRC16带多项式计算法校验
        /// </summary>
        public class BytesCheck
        {
            #region 校验和
            /// <summary>
            /// 计算按位异或校验和（返回校验和值）
            /// </summary>
            /// <param name="Cmd">命令数组</param>
            /// <returns>校验和值</returns>
            public static byte GetXOR(byte[] Cmd)
            {
                byte check = (byte)(Cmd[0] ^ Cmd[1]);
                for (int i = 2; i < Cmd.Length; i++)
                {
                    check = (byte)(check ^ Cmd[i]);
                }
                return check;
            }

            /// <summary>
            /// 计算按位异或校验和（返回包含校验和的完整命令数组）
            /// </summary>
            /// <param name="Cmd">命令数组</param>
            /// <returns>包含校验和的完整命令数组</returns>
            public static byte[] GetXORFull(byte[] Cmd)
            {
                byte check = GetXOR(Cmd);
                List<byte> newCmd = new List<byte>();
                newCmd.AddRange(Cmd);
                newCmd.Add(check);
                return newCmd.ToArray();
            }
            #endregion

            #region CRC16查表法

            #region CRC对应表
            //高位表
            readonly static byte[] CRCHigh = new byte[]{
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 
            0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 
            0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 
            0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 
            0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 
            0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 
            0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 
            0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 
            0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 
            0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 
            0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40};
            //低位表
            readonly static byte[] CRCLow = new byte[]{
            0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 
            0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 
            0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 
            0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 
            0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4, 
            0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3, 
            0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 
            0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 
            0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 
            0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29, 
            0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED, 
            0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26, 
            0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 
            0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 
            0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 
            0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68, 
            0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E, 
            0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5, 
            0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 
            0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 
            0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 
            0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B, 
            0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B, 
            0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C, 
            0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 
            0x43, 0x83, 0x41, 0x81, 0x80, 0x40};
            #endregion

            /// <summary>
            /// 计算CRC16循环校验码
            /// </summary>
            /// <param name="Cmd">命令数组</param>
            /// <param name="IsHighBefore">高位是否在前</param>
            /// <returns>高低位校验码</returns>
            public static byte[] GetCRC16(byte[] Cmd, bool IsHighBefore)
            {
                int index;
                int crc_Low = 0xFF;
                int crc_High = 0xFF;
                for (int i = 0; i < Cmd.Length; i++)
                {
                    index = crc_High ^ (char)Cmd[i];
                    crc_High = crc_Low ^ CRCHigh[index];
                    crc_Low = (byte)CRCLow[index];
                }
                if (IsHighBefore == true)
                {
                    return new byte[2] { (byte)crc_High, (byte)crc_Low };
                }
                else
                {
                    return new byte[2] { (byte)crc_Low, (byte)crc_High };
                }
            }

            /// <summary>
            /// 计算CRC16循环校验码（返回包含校验码的完整命令数组）
            /// </summary>
            /// <param name="Cmd">命令数组</param>
            /// <param name="IsHighBefore">高位是否在前</param>
            /// <returns></returns>
            public static byte[] GetCRC16Full(byte[] Cmd, bool IsHighBefore)
            {
                byte[] check = GetCRC16(Cmd, IsHighBefore);
                List<byte> newCmd = new List<byte>();
                newCmd.AddRange(Cmd);
                newCmd.AddRange(check);
                return newCmd.ToArray();
            }
            #endregion

            #region 多项式参数 CRC16计算
            /// <summary>
            /// 多项式参数 CRC16计算
            /// </summary>
            /// <param name="Cmd">命令</param>
            /// <param name="Poly">多项式</param>
            /// <param name="IsHighBefore">高位是否在前</param>
            /// <returns></returns>
            public static byte[] GetCRC16ByPoly(byte[] Cmd, ushort Poly, bool IsHighBefore)
            {
                byte[] CRC = new byte[2];
                ushort CRCValue = 0xFFFF;
                for (int i = 0; i < Cmd.Length; i++)
                {
                    CRCValue = (ushort)(CRCValue ^ Cmd[i]);
                    for (int j = 0; j < 8; j++)
                    {
                        if ((CRCValue & 0x0001) != 0)
                        {
                            CRCValue = (ushort)((CRCValue >> 1) ^ Poly);
                        }
                        else
                        {
                            CRCValue = (ushort)(CRCValue >> 1);
                        }
                    }
                }
                byte[] Check = BitConverter.GetBytes(CRCValue);
                if (IsHighBefore == true)
                {
                    return new byte[2] { Check[1], Check[0] };
                }
                else
                {
                    return Check;
                }
            }

            /// <summary>
            /// 多项式参数 CRC16计算
            /// </summary>
            /// <param name="Cmd">命令</param>
            /// <param name="Poly">多项式</param>
            /// <param name="IsHighBefore">高位是否在前</param>
            /// <returns></returns>
            public static byte[] GetCRC16ByPolyFull(byte[] Cmd, ushort Poly, bool IsHighBefore)
            {
                byte[] check = GetCRC16ByPoly(Cmd, Poly, IsHighBefore);
                List<byte> newCmd = new List<byte>();
                newCmd.AddRange(Cmd);
                newCmd.AddRange(check);
                return newCmd.ToArray();
            }
            #endregion
        }


}
